js default parameter code example
Example 1: javascript constructor default parameter
function greet(name, greeting, message = greeting + ' ' + name) {
return [name, greeting, message]
}
greet('David', 'Hi') // ["David", "Hi", "Hi David"]
greet('David', 'Hi', 'Happy Birthday!') // ["David", "Hi", "Happy Birthday!"]
Example 2: javascript default parameters
function multiply(a, b = 1) {
return a * b;
}
Example 3: js default parameter
function read_file(file, default_param = false) {
// Code
}
Example 4: js default parameter
function greeting (name = 'stranger') {
console.log(`Hello, ${name}!`)
}
greeting('Nick') // Output: Hello, Nick!
greeting() // Output: Hello, stranger!
Example 5: javascript default function parameter value
function multiply(a, b) {
b = (typeof b !== 'undefined') ? b : 1
return a * b
}
Example 6: javascript parameter default parameter
function say(message='Hi') {
console.log(message);
}
say(); // 'Hi'
say(undefined); // 'Hi'
say('Hello'); // 'Hello'
function date(d = today()) {
console.log(d);
}
function today() {
return (new Date()).toLocaleDateString("en-US");
}
date();
function add(x = 1, y = x, z = x + y) {
return x + y + z;
}
console.log(add()); // 4